Hypothermal effects of cold anesthesia on the vitality and muscle quality of live Chinese mitten crab (Eriocheir sinensis)

Abstract

Crab encounters obstacles like elevated transportation expense and diminished survival rate. In the study, the effects of cold anesthesia (CA), including fast cooling (FC) and slow cooling (SC) anesthesia on the vitality state and muscle quality of Chinese mitten crab were researched. We found firstly that the CA dormancy temperature range of Chinese mitten crab was identified from −2 to 10 °C, and 7 °C was optimal. They could survive for a duration of 10 d when subjected at 7 °C, the survival rate of SC treatment significantly increased to 80.6 %. Compared with the control and FC groups, the Lt50 of crab in the SC group was prolonged, and the mass loss rate, lactic acid content, and oxidative loss of myofibrillar protein (MP) were significantly increased during storage. Moreover, the texture became soft, the myofibrillar structure was broken, the gaps between muscle fibers were enlarged, and the water-holding capacity (WHC) decreased significantly in the control group, while the texture and WHC in CA treatments (FC and SC) had no significant change, especially SC. CA treatments could effectively prevent myofibril destruction, reduce pH fluctuation and protein oxidation, and keep fixed water in the muscle. Of the two CA treatments, SC was more conducive to maintaining muscle quality and vital signs. Therefore, CA treatments not only enhanced survival rate but also inhibited muscle deterioration, especially SC. These findings offered crucial empirical support for advancements in live crab preservation technology and should be validated on a larger scale.